The first machine, the BBC Micro Model A (16KB RAM), introduced in 1981, was designed BBC Computer Literacy Project, operated by the British Broadcasting Corporation (BBC). Designed with an emphasis on education, it was notable for its expandability and the quality of its operating system. Another version with twice the RAM (32KB) and named as the Model B was also released that year.Although it was pretty expensive for its time, and by releasing also on 1983 the Acorn Electron as a budget version (less expensive, less expandable) of the BBC Micro, it was successful enough to hit the home computers market in the UK as some notable game title such as Commando (Capcom / Elite), Barbarian series (Palace Software), Arkanoid (Taito), Bubble Bobble (Taito) and many more have been released. Apart of their great expandability another great featured offered from these systems was that the RAM was clocked twice as fast as the CPU (4 MHz) and making the CPU and memory independent enough from the video display circuits (memory address structure without speed penalties) much like the MSX computers and in contrast to the Amstrad CPC and Sinclair ZX Spectrum! A few years later, the Model B+ (1985) with 64KB RAM and floppy-disk support as standard was also released. Finally the BBC Master was released on 1986, sporting 128KB RAM as standard and many other refinements (extra ROM software, extra paged RAM, second processors fitted internally as plug-ins etc!)